Air hoist



June 20, 1961 R. E. SMITH 2,989,288

AIR HOIST Filed June 3, 1955 3 Sheets-Sheet 1 R. E. SMITH June 20, 1961AIR HOIST 5 Sheets-Sheet 3 Filed June 3, 1955 United Sta es Patent2,989,288 AIR HOIST Ralph E. Smith, Spring Lake, Mich., assignor toGardner- Denver Company, Quincy, 111., a corporation of Dela! ware FiledJune 3, 1955, Ser. No. 513,126 1 C im (C 2 8) The present inventionrelates to hoists and more particularly to a light-duty hoist intendedfor manual manipulation.

It is an object of the present invention to provide an improved hoist inwhich the power unit, together with its associated hook, is suspended atthe lower end of a fixedly anchored supporting cable, the hoist beingreferred to herein for convenience as of the inverted type. It isanother object of the invention to provide a hoist of the above typewhich is ideally suited for picking up loads tinder manual guidancewhich are relatively small, say, on the order of ten pounds to about twohundred pounds for enabling such loads to be swung from the point ofoverhead support laterally through a useful range. It is a relatedobject to provide a hoist in which the load may be easily controlled inits vertical movement and guided horizontally for accurate placement asrequired in the lifting of work pieces from the floor or platform to aposition on a bench or a machine. It is still another object to providea hoist which enables one hand to be used both for guiding and fordetermining direction and rate of lifting or lowering, the other handbeing free to control other parts or machinery.

It is a further object to provide a hoist which is especially useful forrepetitious operations involving the picking up and putting down ofloads formerly requiring the services of a husky workman. It is arelated object to provide a hoist which enables women to take care ofproduction jobs formerly requiring men and 'which enables either a manor Woman to work more comfortably and without fatigue.

It is a still further object to provide a hoist which may be drawndownwardly by application of light manual pressure for hooking on to aload and which makes use of the natural bending and lifting motion ofthe body without, however, requiring the normal lifting effort,permitting the operator to follow his natural impulse to reach downquickly to pick up a work piece. It is an object to provide a manuallymanipulated hoist of the.

inverted type, i.e., having a combined hook and power unit, which may bedrawn downwardly without applying motive power and with an easyfree-wheeling action simulating a condition of perfect counterbalance.

It is an important object of the present invention to provide aninverted hoist which may free-wheel downwardly into a load engagingposition but which causes positive lifting of the load simply bypressing the raise control button and without any intentional clutchingor engaging action on the part of the operator. It is another object toprovide an inverted hoist in which power engagement is not onlyautomatic but direct and positive, insuring against reversion to thefree-wheeling condi tion or'dropping of load. For this: and otherreasons which will be apparent as the discussion proceeds it is anobject of the invention to provide a hoist which is safe and foolproofin operation and which may be manipulated safely by an operator withouttraining or skill.

It is yet another object of the invention, related to the foregoing, toprovide a hoist in which the cable remains taut at all times and underall conditions thereby avoiding the difliculties of snarling which sofrequently accom.

p ny. use of a cable-type, hoist by inexperienced hands. It isfurthermore an object to provide a hoist which is light and 9 41939? a dwhich s suiiuc ent y nexpe sive. as.

, to justify use by a single operator at a single working posig tron ata bench, machine, or station in a production'line;

It is an object to provide a hoist of the above typewhich makes use ofan efiicient high-speed motor and in which speed reduction to normal andsafe lifting speed s is brought about by a novel arrangement of speedreducing elements having a minimum number of parts. It is an" object toprovide a hoist which is not only rapid and efilcient in operation butwhich is easy to install, requir-' ing no overhead tracks or the like,and which may be easily and quickly transferred or removed for benchwork when servicing becomes necessary.

In one of its aspects, it is an object of the invention to provide ahoist particularly suited for powering by a compressed air motor and inwhich the air line is con-' structed and arranged to follow the powerunit of the hoist while remaining in an out-of-the-way position free ofdamage or entanglement with nearby objects. In this connection it isalso an object to provide an air-operated hoist which requires little orno maintenance and in which all the parts are arranged for eiiectivelubrication by oil in the exhaust air and in which the noise level issubstantially lower than that normally associated with hoists of theair-driven type.

It is an object of the present invention to provide, an improved hoistof the inverted type which remains in balance under all conditions andregardless of the amount of cable which has been payed out.

Other objects and advantages of the invention will be-' come apparentupon reference to the attached detailed description and upon studyingthe drawings, in which:

FIGURE 1 is a general view of a hoist constructed in accordance with thepresent invention and showing the manner in which the hoist and load aremanipulated in use.

FIG. 2 is an elevation of the hoist of FIG. 1 together with itsassociated cable and conduit.

FIG. 3 is a diagram, partially schematic, for facilitating understandingof the internal mechanism.

FIG. 4 is a vertical section taken along the line 44 in FIG. 2.

FIG. 5 is a diagram showing the path of the cable within the hoist bodyas viewed along the line 5-5 in FIG. 4.

FIG. 6 is a fragmentary view showing the position of the hook andassociated latch when a load is applied.

FIG. 7 is an exploded perspective of the main elements in the reeldriving mechanism.

FIG, 8 is afragmentary view, partially schematic, of;

the motor and air supply conduits.

FIG. 9 is a section taken through the passages.

FIG. 10 is a section taken through the handle along the line 1 0*10 inFIG}, showing the detailsof: the valve construction.

along the line 11-11 in FIG. 10.

FIG; ll isa fragmentary view of the handle taken 7 While the inventionhas been discussed in connection with the preferred embodiment, it willbe understood I" do not intend to limit the invention thereto but;intend to cover all alternative constructions falling within the spiritand scope of the appended claims.

the present invention having a body 20.

a load 22. Extending upwardly from. the hoist body and in line with thehook 2!]. is a supporting cable 23; having a hook 24 for engagement witha fixed overhead support 2,5. For the purpose of supplying power to the;hoist body. 20 a. conduit 3.0. is. provided encircling the cable;

Patented June 2Q, 1961 motoralong the line 9-9 in FIG. 8, showing themotor inlet and exhaust 23. In the present instance the conduit is inthe form of an air hose coupled to the hoist body at its lower end by asuitable fitting 31 and anchored to the upper end of the cable by aclamp or the like 32. Air is fed into the conduit 30 from any suitablehigh pressure source which preferably includes means for impartinglubricant to the air stream.

The internal mechanism of the hoist is shown in FIG. 4 which is avertical section in the plane of the motor drive shaft; however, it willbe helpful in referring to FIG. 4 to keep in mind FIG. 3 whichillustrates the operation diagrammatically and FIG. 7 which shows someof the parts in perspective. Arranged at one side of the hoist body isan air motor 40 having a rotor 41 and shaft 42. The motor is ofconventional rotary vane type. For the present, it will sufiice to saythat it includes a cylinder 43 mounting end plates 44 and 45, whichplates carry bearings 46, 47 respectively supporting the motor shaft 42.The rotor is of the usual slotted construction having blades 51-56 (FIG.8), the outer ends of which engage the eccentric inner surface 43a ofthe cylinder 43. More detailed reference will be made at a later pointto the means for admitting air to and exhausting air from the motor. Itwill be understood by one skilled in the art that the air is admittedbetween the rotor and cylinder at a point where the inter-blade space isa minimum and the pressure, acting difierentially on the blades, urgesthe rotor around to a point where the air is exhausted, the bladesacting in concert to rotate the shaft 42 at high speed.

Prior to discussing the speed reduction gearing, reference may be madeto the reel 60 on which the cable 23 is wound. In accordance with one ofthe aspects of the present invention, the reel 60 is of a disk shapehaving a relatively narrow slot 60a just slightly larger than thediameter of the cable so that the cable is wound upon the reel in spiralformation. For the purpose of leading the cable 23 from the hoist body,an annular guide or fair-lead 61 is provided which is substantiallycentered over the reel 60 as shown in FIG. 4. For maintaining the cablecentered in the opposite direction a circular guide or roller 62 isprovided having a slot 63, the root of which is aligned with the centerof the fair-lead 61. Consequently, the cable tends to be fed into thefair-lead in aligned position regardless of the amount of cable storedon the reel 60.

In accordance with one of the important aspects of the present inventiona speed-reducing driving train is connected between the motor and thereel having a clutch for enabling free-wheeling of the reel togetherwith means responsive to the presence of a load on the hook forautomatically engaging the clutch to permit raising of the load. Theinvention also contemplates, in association with the above, frictionmeans for inhibiting the paying out of cable when the driving train isin its free wheeling condition so that the body of the hoist issupported in fixed position on the cable, while permitting the hoist tobe drawn quickly downward by light manual efiort preparatory to engagingthe load. In the present instance, the speed reducing gearing employedbetween the motor shaft and the reel 60 is of the differential type andis indicated generally at 70. The gearing includes what may be termed,for convenience, a fixed ring gear 71 and a rotatable ring gear 72, therotatable ring gear being mounted inside an annular sleeve 72 which isintegral with the reel 60 as shown. Such ring gears are arranged side byside with the teeth thereof spanned and in mesh with a pair of planetaryor idler pinions 73, 74 mounted in a rotatable cage 75. The motor shaft42 is centrally arranged within the cage 75 and includes a drive pinion76 at its outer end for meshing with the idler pinions 73, 74. Theannular sleeve 72 is rotatably mounted within the annular member 72"which surrounds the sleeve. In the present instance a bushing 72" whichis held within the annular member, allows the annular sleeve to turnwith a minimum of friction and, as shown, the fixed" ring gear 71 isformed inside the annular member but spaced axially of the bushing.

To bring about the desired high ratio of speed reduction each of theidler pinions consists of two integral portions of unlike diameterarranged side by side, the two portions in the case of the idler pinion73 being designated at 73a and 73b, respectively. The pitch diameter ofthe two ring gears correspondingly differs by a small amount. In apractical case, the pitch diameter of the fixed ring gear 71 may be2.100 inches while the pitch diameter of the movable ring gear 72 is2.033 inches. Upon rotation of the motor shaft in a given direction, themovable ring gear will tend to turn very slowly but with high torque inthe same direction, provided that the fixed ring gear 71 remains fixedin position relativeto the body of the hoist.

For the purpose of applying the controlled frictional drag to the cableunder the free-wheeling condition so as to permit paying out of thecable when the hoist body is drawn manually downward, a friction drag isapplied to the annular member 72" and thus to the fixed. ring gear 71.In the present instance, a friction shoe 80 is used, received in thewall of the hoist body as shown in FIG. 4 and riding on the periphery 81of the annular member 72". To adjust the amount of friction a coilspring 82 is provided having an adjusting screw 83. Since the drivingtrain is non-reversible, i.e., non-retrograde, drawing the hoist bodydownwardly against the force of friction is accompanied by bodilyrotation of the driving train including the two ring gears 71, 72, thedifferential cage and rotor 41 of the motor.

In practicing the invention, means are further provided, as statedabove, for positively clutching the driving train incident to applying aload to the hook 21. Such clutching means in the present instanceincludes a locking plunger 85 for locking the annular member 72" andthus the fixed ring gear 71 in place, the plunger having a lug 86 whichregisters with spaced teeth 87 projecting from the face of the annularmember. As shown in FIG. 4, the locking plunger 85 is mounted forlimited vertical movement and is normally urged to the upper ordisengaged position by means of a coil spring 88. Since the load hook 21is secured to the lower end of. the locking plunger 85, applying a loadto the hook causes the locking member to be drawn downwardly v into theposition shown in FIG. 6, thereby causing the lug 86 to move intoblocking relation with respectto one of the teeth 87 on the annularmember. With the ring gear 71 locked in place, the path of powertransfer, is complete. Thus, rotation of the motor shaft 42 causesplanetary rotation of the idler pinions 73, 74 relative to; the fixedring gear 71. And because of the differencein. diameter of the two ringgears, the movable ring gear 72; is slowly advanced to reel in or payout the cable depending upon direction of rotation of the motor.

In analyzing the operation of the driving train, it is. helpful toconsider it as a difierential having' an input element in the form ofthe motor shaft- 42, an output element in the form of the movable ringgear 72 and a control element in the form of the annular member'72", andthe fixed ring gear 71. When the fixed ring gear-is. locked in place,the path of power flow is complete and, rotation of the motor shaftcauses slow positive rotation. of the reel. However, if the fixed ringgear 71 were permitted to spin freely, rotation of the motor'shaft wouldsimply cause idle rotation of the gearing and no torque would be appliedtothe-reel. The presence of the friction shoe establishes'anintermediate condition, i.e., the gearing is locked in place for smallvalues of transmitted torque but yields when a predetermined torque isexceeded. Thus, when no power is applied to the motor 40 and with thegearing stationary, suflicient reaction torque is transmitted to thereel 60 so that the body of the hoist is suspended ata fixed positionrelative gesaess to its supporting cable 23. The friction is adjusted byturning the adjusting screw 83 so that only light manual p'ressureisrequired in order to overcome the frictional drag and to move the bodyof the hoist downwardly relative to'the cable for engagement of a loadby the hook. Starting the motor to raise the hoist body is accompaniedby movement of the lug 86 into locking position between the teeth 87 sothat from that point on the fixed ring gear is positively locked inplace relative to the body of the hoist.

Continued rotation of the motor is thus eifective, acting through thereduction gearing, to rotate the reel 60, thus winding up the cable 23to raise the load. It

will be apparent that with the ring gear 71 locked by the plication ofthe load, thereby takin'g over control from the friction shoe and nointentional locking movement is required on the part of the operator.

It is part of the present invention to provide a novel guiding andvalving arrangement thereby permitting the hoist to be completelycontrolled and positioned, both vertically and horizontally, by one handof the operator leaving the other hand free to control the load itselfor In the present instance, the guiding arrangement includes ahorizontally. arranged handle 100 which is laterally spaced from the tocontrol associated parts or machinery.

body of the hoist, being connected thereto by an integral arm orextension 101, the handle and arm being arranged at approximately rightangles to form an elbow 102. Located at one end of the handle, in thepresent instance at the elbow 102, are air control valves 103, 104. Bothof these valves are supplied with compressed air from the helicalconduit 30, the air being fed into the body of the hoist through apassage 105 (FIG. 4) which is connected to a passage 106 providedcentrally within the arm 101. For rotation of the motor in the raisedirection the valve 103 has its outlet 107 connected to a motor inletport 103 via a passage 109. In similar fashion, the valve 104 .has itsoutlet '117 connected to inlet port 118 on the motor via a passage 119.The

Ivalves 103, 104 are controlled by buttons 123, 124' (FIG.

10)..' *The specific valve construction does not per se fornra of thepresent invention. For'one skilled in the art it will sufiice to saythat the valves are so arranged that the amount of air supplied to themotor' I is dependent upon the degree to which the valve-buttons 123,1124- are depressed against the force'of return springs 103a, 104a,.respectively. Preferably also, the nonpressurized one of thetwo inletportsis vented to provide, 'what'is termed in the art secondary exhaust.

Incarryingout the invention, the primary exhaust from the motor 40 isvented intothe body of the hoist through a vent opening 125 (FIG. 9')formed in the mo tor {housing Inview of the turbulence and throttlingeffect; which occurs-at the motor, the pressurized exhaust air emitted,fromthe motor into the hoist. body contains finely .;vaporizedlubricant which is dispersed throughout the interiorof the hoist body,eifectively lubricating all of the Working parts. The exhaust air alsoserves to keep the hoist and-its working parts cool even where used'on acontinuous. basis, the exhaust air finally escaping through ports 126(FIG. 4) provided in the side wall.

. -It;;foundrthat one important by-product of the present arrangement isthat' the tortuous path through which the exhaust air must flow acts tomufiie the sound of the air escaping from the motor so that the hoistoperates the hoist otfering..;any impediment. .hoist under suchconditions is just as though the'hoist were accuratelycounterbalanced... The hook isquicklymuch more quietly than conventionalair hoists or conventional air-operated devices. The advantages of theabove construction will be apparent upon considen'nga typical cycle ofoperation. The hoist will normally be stored in an up-raised positionout of the way of the operator but with the handle easily accessible. Inorder to raise a load, foraexample, a box of machine parts, from thefloor or a pallet, the operator simply grasps. the handle, pulling thebody 20 of the hoist downwardly as rapidly as desired- This requiresonly a light force determined by the adjustment of the friction drag8-3. This downward, free wheeling movement is accomplished withoutapplying power to-the motor. The operator may follow his natural impulseto reach quickly-to the floor to raise the object without The feelof'tli'e other engagedwit'h". the. load simply by .pushing the of thehoist a small amount laterally... The. load may, if

.desired, be located at a distance ofseve'ral feet from causes the hookto be shifted outwardly relative to the body of the hoist through a.short distance and causes automatic engagement of the positivelock-permitting transmission of the torque to the reel 60 whichproceedsto wind up .the cable 23 at a rate which is under the control ofthe operator. The speed may be easily controlled at the same time thatthe hand of the operator is guiding the body of the hoist to a positionwhere the load is to be deposited. If necessary, the combined'hoist andload may beswung pendulum-wise to the final location, with the free handof the operator being used to either guide the load on to the positionor to operate other parts or mechanisms. The effectiveness of the onehand control is brought out by the fact 'that 'th'e -h0ist may beefficiently and safely operated even when the operator is disabled-andlacks the use of a second hand. After the load has been raised to thedesired height, the lower button 124 is depressed which allows the loadto settleinto'final position thereby freeing'jthe Having understood theconstruction and operation, it

will-be apparent that the hoist remains constantly in a condition ofbalance, with the hook alignedwith the cable at all times and regardlessof theamount of cable which remains on the reel, and regardless of theamount of loading. Nor is there any tendency for the cable to snare asin-conventional hoists. The cable, since it is loaded by the weight ofthe hoist body, keeps taut, but, even inthe event of momentaryslackening, the turns on the reel maintain thedesired spiralrelationship for unwinding in orderly fashion.

The arrangement described above, is particularly eifctive formachineoperations and the like requiring the lifting of loads in the range oftwenty to one hundred pounds which are conventionally handled by amachine operator, as well as loads somewhat greater than this for which themachine operator would norm'ally'have to call for assistance. It isfeasiblefor the first time to install a hoist directly at a machine orwork station, reducing operator fatigue and making it possible for womento handle jobs normally requiring the services of a man. I

The invention has been described above as embodied in an air hoist, airbeing let in through the helically arranged conduit or air hose 30. Forthe purposeof supporting the air hose with its con-volu-tious spaceduniformly apart, a coiled spring 130 of steel or other suitable metalmay be threaded into the hose. Such spring not only s'upportsthe hoseitself, but may alsoproyide .additionalcounterbalancing for the. body ofthe hoist. 'It

7 Will be apparent to one skilled. in the art that a motor may be usedwhich is driven by other motive power without departing from theinvention. The conduit 30 may; for example, he: an electric conduitsupported and rcinforcedzlry a. coiled spring130. In any event the upperend: or the conduit is desirably anchored to the upper end: of the cable23; The complete combination of hoist body, cable-anrlzconduit',thereforev forms an easy, transportable unit weighing but a few pounds.which may be carried from. one work station: to another simply byunbooking the book 24. So arranged, the conduit is out of way, yet formsa barrier to warn others of the presence; of the relatively thin steelcable when the hoist is in its lowered position.

Iir 'the following claims the term hook has been used for convenience,and it; will. be understood that it is intended to cover any equivalentload-engaging means.

term cable is also. intended to be generic to a flexible, tension memberof any well-known type.

I; claim as my invention:

1". Ina hoist the combination. comprising. a hoist body, a: reel mountedtherein, a cable having one endwound aboutsaid reel and the other endadapted for connection to'a'fixed overhead support, a motor, means forcontrolling application of. power to said motor, a speed-reducingdriving-train connected between said motor and said reel, 21-. loadhook. on. said body, said driving train having a normally engagedfriction coupling having sufiicient friction so. that the hoist body issupported in fixed position on saidcable while permitting the hoist bodyto be drawn downward into load engaging position by light manual eii ortsaidv driving train. having; a positive coupling, enga'geable forpositive driving of the reel by the motor, and means-responsive to-thepresence of load on said hook. for engaging: the positive coupling.

2. In at hoist the combination comprising a hoist body, a reel mountedtherein, acable having one end wound about" said-reel and the other endadaptedv for connection tmasfixed overhead support, a motor, means onsaid hoist body for controlling application of. power to said motor, a--speed-reducing driving; train connected between said motor. andisaidreel, a loadhook on said body,.Said driving trainhaving a normallyengaged friction coupling: and a normally disengaged positive coupling,and means responsive to the presence of load on said hook for engagingthe positive couplingfor raisingof a load by said motor.

3. In a hoist the combination comprising a hoist body, a-zreel: mounted.therein, a cable having, one endwound about: saidreel andathe other endadapted for connection to a fixed; overheadsupport, a motor, aspeed-reducing drivingtrainconnected between said motor and-said reel, aload. hook on said body, said driving train having a friction couplingand apositive drive coupling, a handle onsaidbody for'laterally. guidingthe'same and for. pulling down saidbody'against'the force of thefriction drive connection to a load engaging, position, means responsivetogthe presence of load on said. hook for engaging the positive; drivecoupling, and control meansdirectlyassociwith said handle for operationbythe. guiding hand o fthe iope rator for energizin'gthe motor forrotation in al -desired direction.

4,. Ina.hoist the combination compn'singa hoist body lia "g a book, areel mounted in said body, a cable having one end wound about said reeland therother eiidladaptedforconnectionto a fixed overhead support, am'tor, .a speedneducing driving train. connected between otor andsaidreell and having a positive clutch I ly disengaged for free-wheelingof said reel, a lian l'eo n said'lioistbody for gripping by an operatorfor late al'guidance of the hoistb'ody, means including afriction-elementfor'inhibiting thepaying'out of'cable so thattiie-"liody-of the hoist 'is stationarily supported on saidcxbl'edii'ring-non-use while; permitting the hoist to be drawnquicklydownward by light" manual effort applied to saith-handle; meansresponsive to. the. presence 5 of 'load on said hook for automaticallyengaging the clutch, and control means accessible for operation by theoperator's gripping hand for energizing said motor for rotation in adesired direction.

5. In ahoist the combination comprising a hoistbody having a hook, areel mounted in said body, a cable having one end wound about said reeland the other end adapted for connection to a fixed overhead support,amotor, means for controlling application of power to said motor. aspeed-reducing driving train connected between said motor and said reeland having a normally disengaged clutch for enabling free-wheeling ofsaid reel, means including. a friction element bridging said clutch sothat the body of the hoist is supported in fixed position on said cablewhile permitting the hoist to be drawn quickly downward by light manualeflfort for engagement of the load, and means responsive to the presenceof load on said hook for automatically engaging the clutch for positiveraising of the load by the motor.

6. In a hoist the combination comprising a hoist body having a book, areel'mounted in said body, a cablehaving one end wound about said reeland the other end adapted for connection to a fixed overhead support, amotor, means for controlling application of power to said motor, aspeed-reducing driving train connected between said motor. and said reeland having a clutch for enabling freewheeling of. said reel, meansincluding a friction element for inhibiting the paying out of cable sothat the body of the hoist is supported in fixed position on said cablewhile permitting the hoist to be drawn quickly downward: by light manualeffort for engagementof the load, andmeans responsive to the presence ofload on said hook for automatically engaging the clutch for positiveraising of the load by themotor.

7. In a hoist the combination comprising a hoist body; a reel mounted insaid body; a supporting cable having one end wound about said reel andthe other end adapted for connection to a fixed overhead support; adriving motor. having means for applying power thereto for rotation ofthe motor in one direction or the other; a speedreducing driving trainof the differential type having an input connected to said motor, anoutput connected to said reel, and a rotatable control element; a hookmounted on said body; means providing a friction drag on said controlelement, the friction being sufficient so'that the weight of the saidhoist body suspended on said cable is insufiicient to overcomethefriction drag while permitting the hoist'body to be drawn quicklydownward into load engaging position by application of light manualeffort; and means responsive to thepresence of a load on' said hook forlocking said control element with respect to said hoist body.

8. In a hoist the combination comprising a hoist body, a reelrotatablymounted therein, a cable having one end wound about said reel and havingits other end arranged forconnectiontoafixed overhead support, amotorhaving means for controlling application: of power'thereto, a fixedring. gear and a movable ring gear arranged side by side and of slightlydifferent diameter, aplanetary. pinion spanningsaid ring gears andhaving portions ofunlike diameter meshing therewith, a cage forsupporting. said planetary pinion, means including a drive shaftcoaxially arranged in saideage for coupling said motor and saidplanetary pinion, means providing a friction drag on said fixedringge'ar' so that the body is normally supported by said cable whilepermitting the body to be drawn downwardly by light manual effortaccompanied by rotation of said fixedringgear against the frictionaldrag, a hook on said body, said' book being mounted for limited endwisemovement and having means for biasing the same inwardly with respect tothe body, and l'ockingmeans actua-ted by outward movement of the hookincident tothe pickingup ofa load for lockingsaid fixed ring gear withrespect tothe body.

9; In a hoist'the combination comprising a hoist body;

a reel rotatably mounted therein; having one end wound about said reeland having its other end arranged for connection to -a fixed overheadsupport; a motor having means for controlling application of powerthereto; a differential speed-reducing mechanism having an input coupledto the motor, an output coupled to the reel, and a rotatabledifferential member; means providing a friction drag on saiddifferential member, a hook on said body, said hook being mounted forlimited endwise movement and having means for biasing the same inwardlywith respect to the body; and locking means actuated by outward movementof the hook for locking said differential member with respect to thebody, the friction drag means providing sufficient torque to overcomethe hook biasing means when the motor is energized incident to pickingup of a load.

10. In a hoist the combination comprising a hoist body, a reel mountedtherein, a cable having one end wound about said reel and having meansat its other end adapted for connection to a fixed overhead support, ahook on the underside of said body for engaging a load, a reversiblemotor, means including a step-down drive connection between said motorand said reel, said hoist body providing a generally horizontal handlefor gripping by an operator for lateral guiding of the hoist body andsuspended load, a pair of control buttons arranged one above the otherin said handle adjacent the thumb position of the operator for operationincident to lateral guiding, control means operated by said buttons forapplication of power to the motor for respective raising and lowering ofthe hoist body, and means in said step-down drive connectionautomatically eflective upon application of load to the hoist forbraking said reel against lowering movement to suspend the hoist at afixed position relative to its supporting cable.

11. In a hoist the combination comprising a hoist body and a reelmounted in said body, a cable having one end wound about said reel andhaving the other end adapted for connection to a fixed overhead support,a hook mounted on the underside of said hoist body, a fair-lead mountedat the top of said hoist body in alignment with said hook so that thehook and supporting cable are maintained in alignment independently ofthe amount of cable payed out from said reel, a reversible motor havinga step-down reversible drive connection for rotating said reel, means onsaid hoist body for controlling application of power to said motor, andmeans in said step-down drive connection for braking said reel againstlowering movement to suspend the hoist at a fixed position relative toits supporting cable yet allowing said hoist while under load to beraised and lowered by power.

12. In a hoist the combination comprising a hoist body having a hook onthe underside of said body for carrying a load, a reel rotatably mountedtherein, a cable having one end wound about said reel and having itsother end arranged for connection to a fixed overhead support, a

motor mounted in said hoist body to one side of said reel and having astep-down drive connection for rotating said reel, said reel having anannular sleeve integral therewith and extending to the opposite side ofsaid reel from said motor, an annular member surrounding the free end ofsaid sleeve and rotatably mounting said sleeve in the hoist body, saiddrive connection comprising a drive ring gear formed inside said sleeveadjacent the free end thereof, a differential ring gear of slightlylarger diameter than said drive ring gear mounted in the hoist body andfixed against rotation during operation of the hoist to raise a load,said ring gears being arranged adjacently in the hoist body, idler gearsspanning said ring gears and having portions of unlike diameters meshingtherewith, a cage for supporting said idler gears, and a shaft coaxiallyarranged in said reel and said cage for coupling said motor and saididler gears.

13. In a hoist the combination comprising a hoist body, a reel mountedin said hoist body, a cable having one end wound about said reel and theother end adapted for connection to a fixed overhead support, a hook onthe underside of said body for engaging the load, an air motor having astep down drive connection with said reel, a handle integral with saidhoist body for gripping by an operator for lateral guiding of the hoistbody and a suspended load, a pair of control buttons arranged in saidhandle adjacent the thumb position of the operator for operationincident to lateral guiding, control means operated by said buttons forapplication of power to the motor for respective raising and lowering ofthe hoist body, a flexible air hose for supplying power to said motorthrough said control means, said air hose having a permanent set in theform of a helix, said air hose being arranged substantially coaxially ofsaid cable and having its lower end connected to the hoist and its upperend arranged for anchoring with respect to the overhead support so thatthe helix is elongated when the cable is paid out and shortened when thecable is reeled in.

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